1. Field of Invention
The present invention relates to a packing-integrated type connector in which a break in a seal lip portion of waterproof packing which is formed integrally with a connector housing is prevented as well as a method of manufacturing the same.
2. Related Art
FIGS. 6 to 7 show a conventional packing-integrated type connector and a method of manufacturing the same.
This packing-integrated type connector Cxe2x80x3 is arranged such that rubber-made waterproof packing 30 is formed integrally with a synthetic resin-made connector housing 1.
The connector housing 1 has two terminal accommodating chambers 31 (FIG. 7) arranged in parallel in an elliptic housing body 2, and has a hood portion 10 (FIG. 7) provided concentrically on the outer side of the housing body 2. A terminal retaining lance 32 (FIG. 7) is formed in each of the terminal accommodating chambers 31. A pair of terminal inserting holes 34 for a mating female connector (not shown) are formed in a front end wall 33 of the housing body 2 in such a manner as to continue from the terminal accommodating chambers 31, while a pair of openings 35 (FIG. 7) for inserting female terminals (not shown) into the terminal accommodating chambers 31 are formed in a rear-end portion of the housing body 2. Each of the openings 35 continues to a large diameter portion for inserting and fitting a waterproof rubber plug (not shown).
The packing 30 is provided on the outer periphery of a rear half side of the housing body 2 on the inner side of the hood portion 10. Two seal lip portions 37 which are brought into contact with an inner wall surface of a mating female connector housing (not shown) are formed on a front portion of the packing 30. The seal lip portions 37 are formed projectingly with a greater diameter than that of a peripheral wall portion 38 (FIG. 7) of the packing 30.
As shown in FIG. 7, the formation of the packing 30 is effected by inserting a mold 39 between the hood portion 10 and the housing body 2 to form a packing forming gap 40 and by injecting fluid (liquid) silicone rubber 30xe2x80x2, which is a packing material, into the packing forming gap 40 through an injection hole 17 penetrating a bottom wall 11xe2x80x2 of the hood portion 10. The injection hole 17 continues to a silicone injecting core 4. In addition, a vent hole 15 is provided in a bottom wall 11 of the hood portion 10 on the 180xc2x0 opposite side of the injection hole 17, and the vent hole 15 continues to a vent core 5 on the outer side. The silicone rubber 30xe2x80x2 is injected into the packing forming gap 40 from the silicone injecting core 4, and the air inside the packing forming gap 40 is discharged through the vent hole 15.
With the conventional arrangement, however, since the seal lip portions 37 of the packing 30 are located at a position remote from the silicone injecting core 4, there have been cases where, particularly on the 180xc2x0 opposite side of the silicone injecting core 4 (on the vent core 5 side), the silicone rubber 30xe2x80x2 fails to flow completely round to (fails to fill) seal lip portions 37xe2x80x2 and a break 41 occurs from the time the silicone rubber 30xe2x80x2 is injected into the packing forming gap 40 from the silicone injecting core 4 until it reaches the vent core 5. In the event that the break 41 occurs in the seal lip portions 37xe2x80x2, the waterproof seal characteristic declines, so that such products are inevitably disposed of as defective products, resulting in the deterioration of the yield.
In view of the above-described aspect, an object of the present invention is to provide a packing-integrated type connector in which a break in a seal lip portion of packing due to the short shot of the packing material can be reliably prevented as well as a method of manufacturing the same.
To attain the above object, the present invention adopts a packing-integrated type connector in which a vent hole and packing having a seal lip portion are formed in a connector housing, characterized in that a thin-walled portion is formed on the packing between the seal lip portion and the vent hole, whereby the resistance of flow of a fluid packing material toward the vent hole is increased by the thin-walled portion, thereby allowing the packing material to be reliably filled in the seal lip portion.
It is possible to adopt a structure in which a short-shot preventing rib is formed on the connector housing contiguously to the thin-walled portion. In addition, it is also effective to adopt an arrangement in which a pair of short-shot preventing ribs are formed as the short-shot preventing rib, and the packing continues to the vent hole via the pair of short-shot preventing ribs.
In addition, the present invention also adopts a method of manufacturing a packing-integrated type connector in which a fluid packing material is injected-between a mold and a connector housing, and air is led out from a vent hole in the connector housing so as to form a packing having a seal lip on the connector housing, comprising the steps of: forming a short-shot preventing rib in the mold; and causing the packing material to reach the vent hole via a narrow gap between the short-shot preventing rib and the connector housing.
The short-shot preventing rib may be formed on the connector housing instead of the mold, and the packing material may be caused to reach the vent hole via-a narrow gap between the short-shot preventing rib and the mold. In addition, it is also effective to form a pair of short-shot preventing ribs as the short-shot preventing rib, and cause the packing material to reach the vent hole via the pair of short-shot preventing ribs.